elixir-auth-microsoft

The easy way to add Microsoft OAuth authentication to your Elixir / Phoenix app.

Documented, tested & maintained. So you don't have to think about it. Just plug-and-play in 5 mins.

Why? 🤷
What? 💭
Who? 👥
How? ✅

Why? 🤷

Following Google and Github it made sense for us to add "Sign-in with Microsoft".
This is the package we wished already existed. Now it does!

What? 💭

An Elixir package that seamlessly handles Microsoft OAuth2 Authentication/Authorization in the fewest steps.
Following best practices for security & privacy and avoiding complexity by having sensible defaults for all settings.

We built a lightweight solution that does one thing and is easy for complete beginners to understand/use.
There were already a few available options for adding Microsoft Auth on hex.pm/packages?search=microsoft. Most of these are not specific to Azure AD or build upon other auth packages that have much more implementation steps and complexity. Complexity == Cost. 💸 Both to onboard new devs and maintain your app when there are updates.
This package is the simplest implementation we could conceive. It has both step-by-step setup instructions and a complete working example Phoenix App. See: /demo

Who? 👥

This package is for people building apps with Elixir / Phoenix who want to add "Sign-in with Microsoft" much faster and more maintainably.

It's targetted at complete beginners with no prior experience/knowledge of auth "schemes" or "strategies".
Just follow the detailed instructions and you'll be up-and running in a few minutes minutes.

How? ✅

You can add Microsoft Authentication to your Elixir App using elixir_auth_microsoft
in under 5 minutes the following steps.

1. Add the hex package to `deps` 📦

Open your project's mix.exs file and locate the deps (dependencies) section.
Add a line for :elixir_auth_microsoft in the deps list:

def deps do
  [
    {:elixir_auth_microsoft, "~> 1.1.0"}
  ]
end

Once you have added the line to your mix.exs, remember to run the mix deps.get command in your terminal to download the dependencies.

2. Create an App Registration in Azure Active Directory 🆕

Create an App in Azure Active Directory if you already don't have one.
You need this to generate OAuth2 credentials for the appication.

The Azure AD credentials can either be saved as environment variables or stored in a config file if you prefer.

Note: There are a few steps for creating your Azure App Registration and respective credentials.
We created the following azure_app_registration_guide.md to make it quick and painless.
Don't be intimidated by all the buzz-words; it's quite straightforward.
Once you have followed the instructions in the guide you will have the two secrets you need to proceed.
If you get stuck, get help by opening an issue on GitHub!

3. Export Environment / Application Variables

You may either export these as environment variables or store them as application secrets:

e.g:

export MICROSOFT_CLIENT_SECRET=rDq8Q~.uc-237FryAt-lGu7G1sQkKR
export MICROSOFT_CLIENT_ID=85228de4-cf4f-4249-ae05-247365
export MICROSOFT_SCOPES_LIST=openid profile

Note: These keys aren't valid, they are just for illustration purposes.

alternatively add the following lines to your config/runtime.exs file:

config :elixir_auth_microsoft,
  client_id: "00c63f7-6da6-43bd-a94f-74d36486264a",
  client_secret: "paX8Q~_SRO9~UScMi4GTyw.oC8U_De.MiqDX~dBO"
  scopes: "openid profile"

See: https://hexdocs.pm/phoenix/deployment.html#handling-of-your-application-secrets

The MICROSOFT_SCOPES_LIST or scopes are optional, and they default to the user profile.
For the scopes available, see: learn.microsoft.com/en-us/azure/active-directory/develop/v2-permissions-and-consent

Remember that the scopes you request are only given permission depending on what you set in the App Registration in Azure Active Directory. Find more information in the azure_app_registration_guide.md

A note on tenants

If you need to override some of the default URL endpoints, you can use these environment variables:

export MICROSOFT_AUTHORIZE_URL=https://login.microsoftonline.com/<your_tenant_id>/oauth2/v2.0/authorize
export MICROSOFT_TOKEN_URL=https://login.microsoftonline.com/<your_tenant_id>/oauth2/v2.0/token
export MICROSOFT_PROFILE_URL=...

or alternatively change your config/runtime.exs file to include your custom endpoints

config :elixir_auth_microsoft,
  #...
  authorize_url: "https://login.microsoftonline.com/<your_tenant_id>/oauth2/v2.0/authorize",
  token_url: "https://login.microsoftonline.com/<your_tenant_id>/oauth2/v2.0/token",
  profile_url: ...

If you are using "Accounts in this organizational directory only (Default Directory only - Single tenant)" for "Supported account types" in your Azure AD application setup you must override the MICROSOFT_AUTHORIZE_URL and MICROSOFT_TOKEN_URL environment variables to include your tenant ID as shown above, or else you will get an unauthorized_client error, or an AADSTS500202 error.

Warning

If you don't override the authorize_url and token_url parameters and have the app registration open for users, you may encounter an error:

ErrorInsufficientPermissionsInAccessToken - "Exception of type 'Microsoft.Fast.Profile.Core.Exception.ProfileAccessDeniedException' was thrown."

If this occurs, you need to override the authorize_url and token_url with your tenant_id, as shown above.

4. Add a "Sign in with Microsoft" Button to your App

Add a "Sign in with Microsoft" to the template where you want to display it:

<a href={@oauth_microsoft_url}>
  <img src="https://learn.microsoft.com/en-us/azure/active-directory/develop/media/howto-add-branding-in-azure-ad-apps/ms-symbollockup_signin_light.png" alt="Sign in with Microsoft" />
</a>

To enable this button you need to generate the valid signin URL in the controller that is responsible for this page using ElixirAuthMicrosoft.generate_oauth_url_authorize/2

e.g:

def index(conn, _params) do
  oauth_microsoft_url = ElixirAuthMicrosoft.generate_oauth_url_authorize(conn, "random_uuid_here")
  render(conn, "index.html",[oauth_microsoft_url: oauth_microsoft_url])
end

Note: this is covered in the /demo/README.md.

5. Use the Built-in Functions to Authenticate People

Once you have the necessary environment or config variables in your Elixir/Phoenix App, use the ElixirAuthMicrosoft.get_token/2 and ElixirAuthMicrosoft.get_user_profile functions to handle authentication.

Sample controller code:

defmodule AppWeb.MicrosoftAuthController do
  use AppWeb, :controller

  @doc """
  `index/2` handles the callback from Microsoft Auth API redirect.
  """
  def index(conn, %{"code" => code, "state" => state}) do

    # Perform state change here (to prevent CSRF)
    if state !== "random_state_uid" do
      # error handling
    end

    {:ok, token} = ElixirAuthMicrosoft.get_token(code, conn)
    {:ok, profile} = ElixirAuthMicrosoft.get_user_profile(token.access_token)

    conn
    |> put_view(AppWeb.PageView)
    |> render(:welcome, profile: profile)
  end
end

The exact controller code implementation is up to you,🎉 but we have provided a working example.

6. Add the `/auth/microsoft/callback` to `router.ex`

Open your lib/app_web/router.ex file and locate the section that looks like scope "/", AppWeb do

Add the following line:

get "/auth/microsoft/callback", MicrosoftAuthController, :index

With all that hooked up you should now have everything working.

Note

You can define your callback path with an environment variable MICROSOFT_CALLBACK_PATH or by using the config property :callback_path in your config files.

6.1 Give it a try!

The home page of the app should now have a big "Sign in with Microsoft" button:

When the person clicks the "Sign in with Microsoft" button, they should be prompted with the Microsoft Sign-in page:

This makes it clear what App they are authenticating with, in our case elixir-auth-microsoft-demo (your app will be whatever you called it!)

The person will then have to consent to the defined scopes in the App Registration alongside the overlap of the scope(s) requested.

After this, they will be shown the following page after successful login:

7. Logging the person out

The same way you can log a person in, you should let them logout. This package will do two things:

redirect the person to the Microsoft logout page. This is to end the person's session on Microsoft's identity platform.
clear the app's cookies/session on the client.

In order to add logout capabilities to your application, you need to:

add the redirect URI to your Azure app registration Redirect URIs settings.

optionally, define the redirect URI the person will be redirected to after successfully logging out. This can be the homepage of your application, for example. If this is not set, no redirection occurs. However, setting this option is highly recommended because it will clear the person's session data locally.

7.1 Setting up the post-logout redirect URI

So, for this, you need to set the MICROSOFT_POST_LOGOUT_REDIRECT_URI env variable (or add it to the :post_logout_redirect_uri parameter in the app's config).

export MICROSOFT_POST_LOGOUT_REDIRECT_URI=http://localhost:4000/auth/microsoft/logout

Inside the router.ex file, we'll need to add the redirect URI to the scope.

  scope "/", AppWeb do
    pipe_through :browser

    get "/", PageController, :index
    get "/auth/microsoft/callback", MicrosoftAuthController, :index
    get "/auth/microsoft/logout", MicrosoftAuthController, :logout  # add this
  end

And then define the behaviour inside your MicrosoftAuthController.

  def logout(conn, _params) do

    # Clears token from user session
    conn = conn |> delete_session(:token)

    conn
    |> redirect(to: "/")
  end

This will delete the session locally after the person signs out from Microsoft.

7.2 Add button for person to log out

After this setup, all you need to do is use the ElixirAuthMicrosoft.generate_oauth_url_logout() function to generate the link the person should be redirected to after clicking the Sign Out button.

Done!

That's it! You can chose to do whatever you want after this point. If you have any questions or get stuck, please open an issue. 💬

If you find this package/repo useful, please star on GitHub, so that we know! ⭐

Thank you! 🙏

Testing

If you want pre-defined responses without making real requests when testing, you can add the following property httpoison_mock in your test.exs configuration file.

config :elixir_auth_microsoft,
  httpoison_mock: true

With this setting turned on, calls will return successful requests with mock data.

Of course, you could always a mocking library like mox for this. But if you want a quick way to test your app with this package, this option may be for you!

Complete Working Demo / Example `Phoenix` App 🚀

If you get stuck or need a more in-depth / real-world implementation, we've created a guide that takes you step-by-step through creating a Phoenix app with Microsoft authentication.

Please see: /demo/README.md.

Optimised SVG + CSS Button

If you inspect our demo app, you might have realised we are using an <img> for the Sign in with Microsoft button.

However, we could go for an alternative and have a svg file, making it more lightweight and allowing us to even change languages if we wanted to!

Luckily, Microsoft has made all the heavylifting for us. If we follow this link, we'll find a few options and themes on SVG format.

The result looks better than the <img> button. Here's a comparison between the two:

Notes 📝

Azure AD official docs: https://learn.microsoft.com/en-us/azure/active-directory/
Azure Authentication Flow used: https://learn.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-auth-code-flow#use-the-access-token

Branding Guidelines

The official Microsoft Auth branding guidelines specify exact button, font and spacing: https://learn.microsoft.com/en-us/azure/active-directory/develop/howto-add-branding-in-azure-ad-apps

We have followed them precisely in our implementation.

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README.md

README.md

elixir-auth-microsoft

Why? 🤷

What? 💭

Who? 👥

How? ✅

1. Add the hex package to `deps` 📦

2. Create an App Registration in Azure Active Directory 🆕

3. Export Environment / Application Variables

A note on tenants

4. Add a "Sign in with Microsoft" Button to your App

5. Use the Built-in Functions to Authenticate People

6. Add the `/auth/microsoft/callback` to `router.ex`

6.1 Give it a try!

7. Logging the person out

7.1 Setting up the post-logout redirect URI

7.2 Add button for person to log out

Done!

Testing

Complete Working Demo / Example `Phoenix` App 🚀

Optimised SVG + CSS Button

Notes 📝

Branding Guidelines

Files

README.md

Latest commit

History

README.md

File metadata and controls

elixir-auth-microsoft

Why? 🤷

What? 💭

Who? 👥

How? ✅

1. Add the hex package to deps 📦

2. Create an App Registration in Azure Active Directory 🆕

3. Export Environment / Application Variables

A note on tenants

4. Add a "Sign in with Microsoft" Button to your App

5. Use the Built-in Functions to Authenticate People

6. Add the /auth/microsoft/callback to router.ex

6.1 Give it a try!

7. Logging the person out

7.1 Setting up the post-logout redirect URI

7.2 Add button for person to log out

Done!

Testing

Complete Working Demo / Example Phoenix App 🚀

Optimised SVG + CSS Button

Notes 📝

Branding Guidelines

1. Add the hex package to `deps` 📦

6. Add the `/auth/microsoft/callback` to `router.ex`

Complete Working Demo / Example `Phoenix` App 🚀